So sorry to hear of your loss.
In my youth I saw an acclaimed 'medium' for the experience alone. I'm very sceptical and out of the many things she said, there was only the one sentence I could identify with, and that was about looking out of a window!!
In the past 10 years I've been very good friends with members of the 'mentalism' community: Darren Brown type stuff & have much inside knowledge about how the deceptions are performed, these include knowing personal things about a person you've never met. I can only hint at this but please research the techniques used in 'Coldreading' before you visit any 'medium'.
I don't think you need any medium to feel spiritually connected to your mum. I don't believe in mediums but I've felt very close to people who've left this life already. Feeling your mum is still around & with you in spirit will provide enormous comfort. You don't need a medium to experience this it's on a spiritual level that the mediums words do not compete with.
My sympathies are with you at this very difficult, time, it also helps to talk about it and you are, simply by asking the question above.